What firefighters thought was a routine house fire call turned into a tense standoff in Harbor Gateway after a gunman killed his mother in front of the fire crews.

Initial reports of an "active shooter" in the aftermath of the blaze prompted a massive response by law enforcement in the 700 block of 154th Street shortly after 4:30 a.m., and neighbors were evacuated from their homes.

Firefighters extinguished the flames within 12 minutes at the two-story home. The family of five had escaped the flames, and when firefighters arrived, the mother had immediately asked that the son be put under arrest.

At the same time, the suspect had asked to go back inside the house to retrieve personal items.

"The son, at that time, went back inside the residence ... he came back out armed with a firearm and shot his mother multiple times in the head," said LAPD Capt. Peter Whittingham.

The man, identified as 28-year-old Jose Ramirez, turned the gun on himself and ran back inside the house. The barricade lasted about an hour and a half before the suspect surrendered.

Ramirez was rushed to an area hospital, where he remains in critical condition.